Question: $4xy - 10xz - x + 7 = -9y - 7$ Solve for $x$.
Answer: Combine constant terms on the right. $4xy - 10xz - x + {7} = -9y - {7}$ $4xy - 10xz - x = -9y - {14}$ Notice that all the terms on the left-hand side of the equation have $x$ in them. $4{x}y - 10{x}z - 1{x} = -9y - 14$ Factor out the $x$ ${x} \cdot \left( 4y - 10z - 1 \right) = -9y - 14$ Isolate the $x$ $x \cdot \left( {4y - 10z - 1} \right) = -9y - 14$ $x = \dfrac{ -9y - 14 }{ {4y - 10z - 1} }$ We can simplify this by multiplying the top and bottom by $-1$. $x= \dfrac{9y + 14}{-4y + 10z + 1}$